Cut the beef into bite-sized pieces.
Finely chop the onion.
Heat oil in a pan and sauté the onion.
Add the beef and stir-fry together.
Add soy sauce, sugar, and cooking wine, then mix well.
Place the sautéed beef and onion over rice.
Drizzle mayonnaise on top.
Finish by topping with scallions, seaweed flakes, etc.